The Old Book Gem is a thick, vintage leather-bound book with an orange cover. Centered on the front of the cover is a pink gemstone surrounded by gold decals. There is a yellow bookmark peeking out of its pages.
With the goal of starting a yard sale to raise money for a new library, Steven and Connie search for items to sell in Greg'sstorage unit. Connie finds the Gem Book in the unit and tries to read it, but she stops when it gets boring towards the end. They leave the book in the Beach House with the rest of their inventory for Pearl to find later. Upset with the mess, but in too much of a hurry to organize it all, Pearl instead stores all of the items inside of her gem, including the Book. This results in her feeling ill, leading to Garnet taking Steven into the pocket dimension of Pearl's gem to cure her.
Garnet goads the cause of Pearl's illness to reveal itself, which turns out to be the Gem Book. Acting as a serpent's head, the Book formed a long body made out of a string of books. Garnet and Steven battle the creature, knocking its many books out of Pearl's gem and into the Beach House. Reduced back to a solitary book, the Gem Book tries to flee. Garnet and Steven give chase until it is caught by Steven. He determines that all the Book wanted was to be finished, so he fulfills its wish, putting it to rest. Back at the Beach House, a fed-up Pearl bubbles the Book.